1. Field of the Invention
Pump Structure.
2. Description of the Prior Art
Centrifugal pumps and positive displacement pumps have, in the past, been commonly used in moving fluids and liquids to a desired location. The centrifugal pump, as is well known, obtains its pumping action by whirling the liquid to be pumped at high speeds and allowing the liquid to escape through a suitable chamber and port. Although centrifugal pumps are simple and durable, they usually are inefficient, have little lift capacity, and develop only moderate head pressure. Multi-stage versions of centrifugal pumps are generally used where high head pressures are required, but such pumps ae complicated in design, are expensive, and usually less efficient than a single stage centrifugal pump of equivalent capacity.
In the past, where low capacity and high head pressure is required, positive displacement pumps have frequently been used for this purpose, with the pumps being generally classified as gear, vane, screw, lobe, or of the piston type. Positive displacement pumps are capable of developing high head pressure, but are rarely built in large capacity size, to compete with centrifugal pumps on a volume basis. The commercial reason for limiting positive displacement pumps to those of relative low capacity, is that the cost of building positive displacement pumps of high capacity is prohibitively expensive, with the pumps being excessively bulky compared to a centrifugal pump of equivalent capacity.
The primary purpose in developing the present invention is to provide a pump having a performance not common to the prior art pumps of the centrifugal and positive displacement types. The present pump, for example, in the larger sizes has external dimensions that will be less than centrifugal pumps of like capacity, and with the pressure not possible with single stage centrifugal pumps. The present invention has no physical contact between moving parts within the pump chamber, and as a result has a projected long useful operating life compared to centrifugal pumps. Due to the present invention's low cost, durability, compactness, and efficiency in operation, it is anticipated that the present invention will not only eventually replace many high capacity centrifugal pumps, but will also open a pump market not currently regarded as practical with present-day pumping equipment.
A primary object of the present invention is to supply a semi-positive displacement pump that has operational advantages not common to prior art centrifugal and positive displacement pumps and more specifically a pump of modular structure that may be modified as to the transmission ratio at which the pump operates as well as the rate of discharge, has a high discharge capacity relative to its size, can develop a high head pressure, is reversible as to flow, is self-lubricating, and requires a minimum of maintenance attention due to having no movable components in rubbing contact with the pump chamber.
Another object of the invention is to provide a pump which in the low capacity sizes may be selectively operated by manual means, or by power means, and with the pump capable of being built from standard commercially available materials at a low cost, and this low cost coupled with the efficiency of operation of the pump encouraging the widespread use thereof both for low and high capacity needs.